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(N0 Model.) 3 Sheets-Sheet '1.

H. J. fiLLER.

VACUUM PUMP- No. 264,329. Patented Sept. 12, 1882.

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VACUUM PUMP.

No. 264,329., Patented Sept. 12, 1882.

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(No Model.) 3 Sheets-Sheet 3. H. MULLER.

. VACUUM PUMP. No. 264,329. Patented Sept. 12, 1882.

N. PETERS. Photo-Lithographer: Waihmglfln. D. c.

UNlTED STATES ATEN-T T FFlGE-o HANS J. MULLER, OF NE\V YORK, N. Y.,ASSIGNOR OF ONE-HALF TO ALEX.- ANDER LEVETT, OF SAME PLACE.

VACUUM-PUMP.

SPECIFICATION forming part of Letters Patent No. 264,3Q9, datedSeptember 12, 1882,

Application filed April 28, 1882.

Be it known that I, HANsJ. BIULLEIQOE' the city, county, and State ofNew York, have invented anew and useful Improvement in Vacuum-Pumps, ofwhich the following is a 5 specification.

The object of my invention is to obtain all the advantages of theSprengel orgravity'pump in regard to completeness of vacuum, and toassist its action by means of the mechanical 1o pump, while at the sametime the mechanical pump continually supplies the mercury to thegravity-pump, the mercury being continually drawn from and returned tothe well in which the air escapes that is drawn from the vacuumchamber.v

In thcaccompanying drawings, Figure 3 represents a side view of thedevice embodying my invention, the principal parts being represented invertical longitudinal section. Figs. 1 and 2 show the same enlarged.

Similar letters indicate like parts.

Arepresentsthevacuum-chamber,construct ed in any suitable manner. 'It ishere shown as a glass globe fastened upon abottom plate, and within thechamber is the usual device for indicating pressure. From the bottomplate of said vacuuinchamber a tube, B B, leads toward the pump, and asecond tube, 0, with suitable cut-off valve at leads toward any electriclamps or other devices which are to be attached and exhausted.

D is the Sprengel or gravity pump, constructed in the usual form,consisting of a glass air or vacuum chamber, having the tube extendingfrom the top nearly to the bottom and the tube F leading from the bottomdirectly beneath the tube E. The tubeE leads to the top of the tube Efrom the mechanical pump, and the tube Fleads from the bottom of F tothe mechanical pump.

G is the mechanical pump, containing two pistons or plungers, H and J,both of which are actuated, in the usual manner, by means of the crank Kupon the shaft L, to. which motion is imparted by the wheel M. Theplungers H and J move vertically in the cylinderchambers N and O. Fromthe cylinder-chamber O the tubes X 1? lead to the mercury-well R, and tothe cylinder-chamber Nthe tubes Q W lead from themercury-well B. ThiswellR (No model.)

is open at the top for the escape of air. The valves S T U V upon thetubes E, F, P, and Q, respectively, are all constructed so as to openupward automatically by means of pressure from below or suction fromabove, as shown in S,which represents, in vertical section, an ordinaryglobe-valve. The tubes E and Q are both connected with thecylinder-chamber N by means of the common tube W, and the tubes F and Pare both connected with the cylinderchamber 0 by means of the commontube K. At points where leakage of air is likely to occur in the pump Imake mercury joints Y Y Z by means of caps filled with mercury, in amanner well known in the art, and shown in section at Y. Z Z are twosuch mercury joints at the top of the cylinder-chambers N 0, theplungers passing through the mercury in the cups forming .said joints. Ialso cover the mercury in all thesejoints, as well as the mercury in thewellR with oil, to prevent C(HIOsiOll. The operation of the device is asfollows: The mercury-well R is first tilled with mercury. \Vhen power isapplied to the shaft L the plungers H and J rise simultaneously in thecylinder-chainbers N and 0, and by suction lift the valves V and T,respectively, while the valves S and U by the same power of suction.remain closed. Mercury is drawn from the mercury-well 1% up the tube Qand through the valve V and tube into the chamber N, and air is drawnfrom the vacuum-chamber A through the tube B B, and from the gravitypump D through the tubes F F, and from the tubes E E through the valve Tand tube X into the chamber 0, this exhausting action extending throughthe entire device into which the valve T opens, but the suction from theplunger J not being sufficiently strong at any time to open the valve Sagainst the suction caused by the plunger H. The two plungers now beinglifted and the chamber N being thus filled with mercury and the chamber0 with air, the plungers H and J nextdescend simultaneously, and bypressure upon the contents of the chambers close the valves V and T andopen the valves S and U', thus forcing the mercury through the valve Sinto the tube E, and forcing the air through the valve U into the tube'P. By the action of this double-piston pump, as above described, thetube E E,leading to the Sprengel or gravity pump D, is, after a fewstrokes, filled with mercury, and a portion of the air in the tube P isforced at the same time to the mercury-well R, and, rising to the top ofthe well, escapes. The action of the gravitypump commences when themercury begins to flow from the bottom of the tube E into the top of thetube F. This flow of mercury from the tube E, caused by the fall of theplunger H, and also by the gravity of the mercury itself, will be inregular pulsationscorresponding with the strokes of the mechanical pump,and in the interval between each of these pulsationsnamely, while theplungers H and J are rising-the exhaust action of the plunger Jwvillcarry the mercury from the gravity-pump D into the tube F, leaving anair-space above it in the tube, as shown at the top of F, air beingdrawn at the same time from the vacuumchamber A through the tubeB intothe chamber D. The exhaust action of the plunger J must always draw themercury down into the tube F so far that there will be an air-vacuumspace around the lower end of E and extending somedistance into the tubeF. When the mercury again flows from E at the next descent of theplungers, it will fall into the tube F, but will leave the' air-space inthat; tube above the mercury thatflowed in thepreceding pulsation. Thusthe tube F F will soon be tilled with mercury and air in alternatelayers, and this will be drawn into the chamber 0. The plunger J, in itsdescent, will then force the mercury and air through the valve U intothe tube P, and thus down into the mercurywell, the air escaping, asbefore described, and as much mercury fiowinginto the well at eachdownward stroke of the pump as is drawn from the well by the upwardstrokes. The well is thus continuouslysupplied. Theairin thevacuum-chamber is thus continuously exhausted,

and its tenacity will be measured not only by thegage within thechamber,but by the sizeof the air-spaces in the tube F, for the airchamber ofthe gravity-pump D, together with its arms B and F, should preferablybemade of glass blown in one piece, in order. that the operation of thepumps may be examined. When the air-spaces in the tube F disappear, andthe mercury in falling from the tube E comes in direct contact with themercury in the tube F without any air-space between them, then it willbe that a complete vacuum is formed in the chamber A.

That which I claim is- 1. The combination, with a gravity-pump, of amechanical pump having two pistons operated simultaneously, and withtubes connecting said mechanical pump with the gravitypump,substantially as described, whereby liquid is forced into saidgravity-pump and discharged therefrotmsubstantially as set forth.

2. The combination,witb a gravity-pump, of a mechanical pump and a wellor reservoir, and tubes connecting the reservoir with the mechanicalpump, and the mechanical pump with the gravity-pump, substantially asdescribed, so that the liquid for said gravitypump may be forced intothe same in regular pulsations.

3. The combination of a gravity-pump with a mechanical pump, well orreservoir, and tubes connecting the reservoir with the mechanicalpump,and themechanical pump with the gravity-pump, and the gravity-pumpwith the reservoir, whereby liquid for the gravitypump may beautomatically drawn from the well, supplied to the gravity-pump, andreturned theret'rom to the well, substantially as described.

HANS J. MULLER. In presence of (J. WYLLYs BETTS, JOSEPH H. MARVIN.

